The invention is based on a priority application EP08290111.7 which is hereby incorporated by reference.
The invention relates to a method for coordinating measurements and calibrations in a passive optical network, PON, in particular a Gigabit PON, and to a computer program product for implementing the method. The invention further relates to an optical network termination, ONT, and to a PON comprising at least one such ONT.
At the moment, new embedded measurement methods are being developed which will be integrated into the network management of future GPONs in order to measure the optical line profile via “optical time domain reflectometry” (OTDR). “Embedded” means that the PON doesn't have to be taken offline to perform the measurements, so that the measurements can be performed while the network is running. Typically, the measurements are performed on the wavelength of the actual data transmissions. However, certain calibrations and measurements need a special time window where no upstream data should be transmitted. For these time critical calibrations and measurements, coordination is required such that a minimum of time is needed to perform them in all affected parts (ONTs/Optical Network Units, ONUs) of the PON.
At present, for performing line profile measurements at the actual data transmission wavelength, the whole network has to be turned down. However, this is not an acceptable solution because a passive optical network is dependent on continuos operation (e.g. for synchronization and multimedia streams that should not be interrupted). Another option is to do line profile measurements at a different wavelength, but such measurements are not as accurate as measurements at the actual data transmission wavelength and not applicable in next generation wavelength division mulitplex (WDM) networks.